Human skin color is determined by various factors, including the activity of melanocytes which produce the melanin pigment, distribution of blood vessels, skin thickness, presence or absence of pigments such as carotenoids and bilirubin, or the like. Of the factors, the dark pigment melanin which is produced from melanocytes by the action of many enzymes including tyrosinase is the most important.
The production of melanin is affected by genetic factors, physiological factors such as hormones, stress, etc. and environmental factors such as UV. Existing in the epidermis, the outermost skin layer, melanin protects the skin below from UV, etc. and reduces the generation of free radicals, thereby protecting proteins and genes in the skin. However, excessive production of melanin leads to the formation of chloasma, freckles, etc. as well as accelerating skin aging and inducing skin cancer.
From long ago, ascorbic acid, kojic acid, arbutin, hydroquinone, glutathione, their derivatives, or compounds having tyrosinase inhibition activity have been used in cosmetics or drugs in order to treat or ameliorate anomalous skin pigmentation such as chloasma, freckles, pigmentation, etc. and excessive melanin pigmentation caused by exposure to UV. However, their use is restricted because of insufficient skin whitening effect, safety issue on skin, formulation instability when used in cosmetics, or the like. Thus, researches are under way on natural substances having superior safety and excellent skin whitening activity.
Meanwhile, the nutmeg is a nut of Myristica fragrans which is a perennial plant cultured in tropical regions, and has been used as spices for a long time. In addition, the extract of the aril of nutmeg is peel region of the said fruit of Myristica fragrans and is reported that it has inhibition of proliferation of Helicobacter pylori (In Vivo., 17;541-4, 2003), activation of detoxification in liver (Food Chem. Toxicol., 31;517-21, 1993), chemical prevention of skin verruca (Cancer Lett., 56;59-63, 1991), anti-inflammation activity (Jpn. J. Pharmacol., 49;155-63, 1999). However, the relationship between the nutmeg or the aril of nutmeg and skin whitening activity has never been reported as yet.
Particularly, macelignan extracted from said nutmeg or the extract of the aril of nutmeg is a representative lignan-type compound (Phytochemistry, 59: 169-173, 2002), and it has activity promoting activation of caspase-3 which induces apoptosis (Biol. Pharm. Bull., 27: 1305-1307, 2004), antibacterial activity in oral microorganism (Korean Patent Publication Bulletin No. 10-691792), antiinflammation activity (Korean Patent Publication Bulletin No. 10-0579752), antiacne activity (Korean Patent Publication Bulletin No. 10-0567431), activity inhibiting lipid hyperoxidation of brain cell and active oxigen generation (Biochem. Biophys. Res. Commu., 331: 1264-1269). However, there is still no report whether the austrobailignan 7 or licarin E which could be extracted from the nutmeg or the extract of the aril of nutmeg as well as the said macelignan has skin whitening activity or not.